Optical wavelength communication systems are highly desirable for use in many different applications. Such systems can be used to replace radio frequency systems, such as those used in fast food restaurants, since the optical wavelength carrier does not require special government licenses and are more tolerant of noise interference. For example, short range optical wavelength carrier communication systems are disclosed in the foregoing mentioned co-pending U.S. patent applications. In the co-pending applications, each optical wavelength communication system enables full duplex communication between two or more transceivers. In at least one of the systems disclosed in the foregoing mentioned co-pending applications, both remote and repeating base station transceivers communicate simultaneously with one another over optical wavelength carriers in a full duplex mode of operation. Since the transceivers employ light frequency carriers, both transceivers must be disposed in direct line of sight communication relative to one another. While such optical wavelength carrier systems may be highly usable for many applications, it would be highly desirable to have such an optical wavelength communication system, which enables at least some of the transceivers to be carried from place to place within the same room. For example, in a fast food restaurant, it is desirable to enable the employees to communicate with one another, as they walk between work stations, during the course of the day, while performing their duties.
In actual use, such an antenna and two-way communication system could be used to permit communication between various work stations and workers as they move about through the restaurant from one work station to another. Thus, such a communication system and antenna would not only be able to transmit and receive signals from a fixed work station, but should also be able to communicate with the workers at such work stations as they move from one station to another within the same large, open room. Such a room may be as long as 30 feet in length.
Due to the size of the room, in order to maintain line-of-sight optical communication, several stationary repeating base station transceivers are required to be spaced throughout the room, to insure continuous communication with a plurality of portable remote communication transceivers carried by employees
Thus, it would be highly desirable to employ only a single base station having an antenna system, which can communicate with all portable remote transceivers being carried from place to place in the same large room. However, the cost of the additional stationary base stations is undesirable. Also, there is added expense in labor to install the additional units within the customer's place of business. Moreover, for any given location, it may be difficult, or even impossible, to install a multiplicity of base stations throughout the room, due to the positioning of other equipment within the room.
Several formidable problems have been encountered. For example, the light wave carrier signals generated from a single base station antenna must be capable of being received by the portable units disposed within a given geographical area, regardless of various fixtures and other obstructions which may be disposed within the transmission area. In this regard, since infrared systems are founded on a direct line of sight basis and have a transmission/reception lobe wherein such signals may be communicated, an obstruction disposed within the lobe between a transmitting antenna and a receiving antenna, the communications will necessarily be interrupted.
Therefore, it would be highly desirable to have a new and improved infrared full duplex, communication system and method of using only a single base station for a given large room, and yet the new and improved system would help to eliminate, or at least to greatly reduce, unwanted interrupted infrared communications, due to obstructions and the like.
Similarly, the base station transceiver must be capable of generating a sufficient amount of optical energy to permit the transceivers to be operated satisfactorily in day light, or in bright artificial light conditions. In this regard, in the normal working environment, workers must have adequate light to carry out the normal working tasks. However, strong or bright ambient light tends to interfere with photosensitive diodes so that receptive communication can be greatly hindered or impeded
Therefore, it would be highly desirable to have an infrared system and method of using the same to facilitate transmitting and receiving infrared communication signals between portable infrared remote and base station transceiver, while being used in a brightly lighted area and from substantially any location within that given geographical area.
Another problem associated with a single base station transceiver has been signal interference developed between the infrared signals being transmitted by the base station antenna, and the reception of signals being transmitted by the portable remote transceivers. In this regard, it has been difficult, if not impossible to prevent the infrared carrier signals being transmitted by the base station transceiver from also being received by the base station without resorting to special fiberoptical communication paths, light shields or other similar devices to prevent such interference in communications.
Therefore, it would be highly desirable to have a new and improved infrared system and method of using the antenna, which would substantially eliminate the reception of infrared signals transmitted by the antenna itself. Such a system should be limited to a single stationary base station transmitter for a given room, to help reduce the overall cost of the system, as well as the initial installation expense for such a system.